This invention relates to nonvolatile memory systems and to methods of operating nonvolatile memory systems.
Modular, portable, non-volatile memory devices are available that can be readily connected to and disconnected from host devices such as digital cameras, digital audio recorders, and personal computers. Traditional memory such as flash cards used in these devices is rewritable, allowing a memory address to be erased and rewritten for system or user purposes. The creation of lower-cost memory technologies that are either one-time programmable (OTP) or few-time programmable (FTP) allow new usage models with host devices that are analogous to film in an analog camera where one can simply take and print pictures while saving the low-cost card as a “negative.” Ideally, one would be able to use this low-cost card in a standard flash camera, but the technologies are not necessarily compatible, as portable devices typically use the DOS FAT12/16 file system, which requires system structures to be erasable. Updating the firmware in the device with a file system customized for OTP or FTP memory technology can solve this problem, but this would limit the total available market to new cameras with the software upgrade or else would require users to upgrade their existing cameras with software in the field.